Conventional peanut butter is prepared from shelled peanuts roasted at about 170.degree. C., which are thereafter cooled to about 30.degree. C. These roasted peanuts are then blanched, the skins and nibs are removed and the blanched kernels are split into halves. The blanched, split peanuts are then coarsely ground and to the coarsely ground nuts are added optional ingredients, such as sweetener, salt and hydrogenated vegetable oil. All of the ingredients are thoroughly mixed and are then finely ground. This mixture is then cooled and packed into jars.
Peanut butter is a highly nutritious food containing high levels of protein. However, peanut butter also contains relatively large quantities of fat. A typical peanut butter product will have an oil content of about 50%, a protein content of about 29% and a fiber content of 1% to 2%. Sugars, carbohydrates and moisture normally constitute the rest of the product. The moisture level is usually less than about 2%. Due to the low moisture level and the high level of oil, peanut butter is a highly stable product which can be kept unrefrigerated for substantial periods of time.
To be labeled "peanut butter" under the applicable regulations of the United States Food and Drug Administration, the peanut ingredients must comprise at least 90% of the weight of the finished product, 21 C.F.R. .sctn.164,150. If more than 10% of the peanut product consists of non-peanut ingredients, then the product may be termed a "peanut spread", 21 C.F.R. .sctn.102.23(a) so long as it meets all of the conditions set forth in 21 C.F.R. .sctn.102.23(b). One of these conditions is that the protein content of the product is at least 24% by weight of the finished product.
There has been a substantial amount of research directed to reducing the oil content and, thus, the calorie content of peanut butter. One of the most common methods for effectively decreasing the amount of calories per unit volume in food products is the addition of water as a non-calorie ingredient together with a thickener or emulsifier to duplicate the texture of the original product. However, the addition of water adversely affects the flavor, color, texture and mouthfeel of peanut butter products. More importantly, unlike peanut butter which is microbiologically stable at room temperature of the high level of oil and the low level of water, generally about 1-2% by weight, peanut butter products having high levels of water must usually be refrigerated after opening even if the peanut butter products contain preservatives to retard spoilage.
Replacement of oil with bulking agents has been proposed. U.S. Pat. No. 4,814,195 to Yokoama, et al. is directed to a reduced calorie peanut butter product containing from about 15% to about 40% by weight of a solid bulking agent selected from polydextrose and microcrystalline cellulose.
U.S. Pat. No. 4,828,868 to Lasden, et al. is directed to a low calorie, low fat peanut butter-like product and a method for making the product. In the method, unroasted defatted or partially defatted peanut flour having no more than about 35% fat by weight is milled in the presence of water to a maximum particle size of about 150 microns. The mixture of water and peanut flour is then cooked at a temperature of between about 175.degree. F. and the boiling point of the mixture of peanut flour and water. The moisture level of the finished product is high and it is indicated in the Lasden, et al. patent that the product requires refrigeration for extended shelf life. While the Lasden, et al. patent indicates that defatted peanut flours that have as little as 1% fat can be used, no specific examples are provided as to how to produce a peanut butter product having as low as 1% fat.
U.S. Pat. No. 5,258,192 to Zook, et al. is directed to the production of low calorie nut products and a process for making them. It is taught that low calorie triglycerides may be substituted for nut oils in the manufacture of nut products. The low calorie triglycerides are described in detail. On the simplest level, they are esters of glycerol in which the normal random distribution of fatty acids has been replaced by a precisely defined distribution of long (C.sub.16 -C.sub.40) and short C.sub.2 -C.sub.5) chain fatty acids. In every other regard, these low calorie triglycerides are identical to those found in nature, and indeed to those found in the nut oils which they are replacing.
A major distinction between the Zook, et al. patent and the present invention is the fact that the polyol fatty acid polyesters described herein are not triglycerides. They are low calorie (in the case of polyglycerol polyesters) and noncaloric (in the case of the sugar or sugar alcohol polyesters) substitutes for triglyceride fat. Although functionally similar, they are structurally dissimilar to triglyceride fats and oils.
Preparation of partially defatted nuts and subsequent reexpansion of the nuts by steaming or cooking is well known in the art (U.S. Pat. No. 2,003,415 to Ammann and U.S. Pat. No. 3,294,549 to Vix, et al.). Contacting partially defatted nuts with glycerol before roasting is also known (U.S. Pat. No. 4,049,833 to Gannis, et al.). Pressing pre-roasted nuts has also been described (U.S. Pat. No. 4,329,375 to Holloway, et al.).
The teachings that are found in the Zook, et al. patent include a variety of methods for preparing nuts and nut products from partially defatted nuts which are contacted either before or after roasting with the low calorie triglyceride substance. The triglyceride material is infused into the partially defatted nuts or combined with a flour made from roasted, partially defatted nuts. Infusion of the nuts with triglyceride can be carried out by soaking them in a bath, coating or spraying them, using various temperature and pressure protocols. The nuts, either before or after reconstitution, are roasted by conventional procedures which are described fully in the patent. In none of these teachings is anything other than triglyceride fat mentioned as being an appropriate medium for reconstituting or roasting the nuts.
Furthermore, the Zook, et al. patent teaches that nut butter products, instead of using whole, split or pieces of nuts, is made with a defatted nut flour. In accordance with the present invention, the best nut butter product is made from granular pieces, and the product made from the defatted nut flour, while lower in calories, is inferior in taste and texture.
It would be highly desirable to provide a flexible method for preparation of lowered fat peanut butter products having from about 70% to less than 1% of the metabolizable fat normally associated with peanut butter, i.e., a total peanut oil content of from about 1% to about 35%.
Accordingly, it is a principal object of the present invention to provide a method for the manufacture of lowered fat, lowered calorie peanut butter products.
The present invention provides a peanut butter analog which provides a desirable reduction in metabolizable fat and adds an additional benefit of a reduction in calories. The creamy properties of peanut butter, which are inherently provided by the peanut oil, are supplied by fatty materials which are non-digestible as compared to peanut oil. The peanut butter analogs are equivalent to conventional peanut butter and have flavor, body and texture resembling that of conventional peanut butter.